Network infrastructures may employ multiple layer networks. For example, a network may comprise both an Internet Protocol (IP) network layer, as well as an optical network layer. Often, the separate network layers will exhibit different bandwidth availability at a particular time and for a particular application.
Multiprotocol Label Switching (MPLS) is a mechanism in high-performance networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. The labels identify virtual links (paths) between distant nodes rather than endpoints. MPLS can encapsulate packets of various network protocols. The Generalized Multi-Protocol Label Switching (GMPLS) is a protocol suite extending MPLS to manage further classes of interfaces and switching technologies other than packet interfaces and switching, such as time division multiplex, layer-2 switch, wavelength switch and fiber-switch.
A path computation element (PCE) is a system component, application, or network node that is capable of determining and finding a suitable route for conveying data between a source and a destination. In MPLS and GMPLS networks, the PCE is used to determine the path through the network that traffic should follow, and provides the route for each Label Switch Path (LSP) that is set up. A PCE might be a network node, network management station, or dedicated computational platform that is resource-aware and has the ability to consider multiple constraints for sophisticated path computation.